JP2007291681A - Pit lid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost and enhance assembling property while generally securing a good slip prevention function in a pit lid capable of opening and closing the opening of a pit groove recessed in an installation surface which can be walked and having at least one cover body formed in a hollow closed section structure of a rectangular shape in cross section by extrusion molding or drawing molding. <P>SOLUTION: Ridge groups A, B, C each of which is formed of a set of small ridges t arranged parallel with each other in the extrusion molding or drawing molding direction are molded on the upper surface of the cover body Tm simultaneously with the extrusion molding or the drawing molding. Each small ridge t has an engagement groove extending in the molding direction in the both right and left side-surfaces. A slip prevention plate S capable of performing a slip prevention action in at least two vertical and lateral directions is fitted between the engagement groove of the small ridge t positioned on one or both sides of at least one set of ridge grooves A, B, C and the engagement groove of the small ridge t of the other set of ridges A, B, C facing that engagement groove. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pit cover that can open and close an opening of a pit groove that is recessed in a walking installation surface (for example, an indoor floor surface or an outdoor ground surface).

  The pit grooves used for wiring cable storage, water supply / drainage, and other applications are provided with a pit lid that closes the open upper surface (that is, the opening of the installation surface) and the installation surface is substantially flush with the installation surface.

  The lid body of such a pit lid needs to secure a sufficient bending rigidity so that it can withstand the weight of a pedestrian or the like. Usually, a reinforcing material is fixed, but these technical means have problems such as an increase in the weight of the cover as a whole and an excessive increase in the thickness of the cover itself.

  Therefore, in order to solve this problem, in recent years, it has been proposed that the lid body of the pit lid has a hollow closed cross-section structure by extrusion molding or pultrusion molding, and the lid body is extruded or drawn on the upper surface of the lid body. Forming a plurality of sets of ridges each composed of a plurality of sets of small ridges extending in the molding direction of the molding and arranged in close proximity to each other and simultaneously with the extrusion or pultrusion, The thing using these protrusions for slip prevention is proposed. (See Patent Document 1 below).

  However, in the above-mentioned proposal, since each protrusion group for preventing slip extends linearly in the molding direction of the extrusion molding or pultrusion of the lid body, the slip prevention has directionality and is sufficient in many directions. There is a problem that the anti-slip function cannot be exhibited.

Further, in order to solve such a problem, for example, there has been proposed a method in which a non-slip plate having an uneven surface capable of exhibiting multi-directional anti-slip action is fixed to the flat upper surface of the lid body (described below). (See Patent Document 2).
JP 7-310360 A JP 2003-342967 A

  In the thing of the said patent document 2, in order to fix an anti-slip | skid board to a lid main body upper surface, it is necessary to use special fixing means, such as a volt | bolt and a rivet, and there is a problem that the fixing operation | work becomes complicated as it increases cost. is there.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a pit cover that can solve the above-mentioned problems of the conventional one at a stroke.

  In order to achieve the above object, the invention of claim 1 is a pit lid capable of opening and closing an opening of a pit groove recessed in a walkable installation surface, and is a hollow closure having a rectangular cross section by extrusion molding or pultrusion molding. At least one lid body formed in a cross-sectional structure, and each upper surface of the lid body is composed of a set of a plurality of small ridges extending in the molding direction of the extrusion molding or pultrusion molding and arranged close to each other The plurality of sets of protruding ridges are formed to be spaced apart from each other and simultaneously with the extrusion molding or pultrusion molding, and each small ridge is formed on the left and right side surfaces of the small ridge in the molding direction. Each of the extending grooves has an extending engaging groove, and the engaging grooves of the small protrusions located on one side or both sides of at least one set of the protruding protrusion groups, and the small protrusions of the other set of protruding protrusions facing each other. At least two directions in the vertical and horizontal directions between the engaging groove of the ridge Characterized in that fitted the slip plate capable of exhibiting slip effect.

  The invention of claim 2 is a pit lid capable of opening and closing an opening of a pit groove recessed in a walking installation surface, and formed into a hollow closed cross-sectional structure having a rectangular cross section by extrusion molding or pultrusion molding. And a plurality of sets of protrusions each including a plurality of sets of small protrusions extending in the forming direction of the extrusion molding or pultrusion molding and arranged in close proximity to each other. In the case where the strips are formed apart from each other and at the same time as the extrusion molding or the pultrusion molding, each small protrusion has an engaging groove extending in the forming direction on the left and right side surfaces of the small protrusion. The at least one set of protrusions is covered with an anti-slip plate capable of exhibiting an anti-slip action in at least two vertical and horizontal directions, and the anti-slip plate includes a plurality of small protrusions immediately below the anti-slip plate. Between the engaging grooves facing each other. Wherein the integrally has an engaging projection to be respectively fitted to the lower surface.

  Furthermore, the invention of claim 3 is a pit lid capable of opening and closing an opening of a pit groove recessed in a walking installation surface, and formed into a hollow closed cross-sectional structure having a rectangular cross section by extrusion molding or pultrusion molding. At least two lid bodies are arranged in parallel on the left and right sides, and adjacent ends of adjacent lid bodies are detachably coupled. A plurality of projections each extending in the molding direction of the molding or pultrusion and arranged in close proximity to each other, the ridges being spaced apart from each other and the extrusion or pultrusion of each lid body; Each of the small ridges formed at the same time has engaging grooves extending in the molding direction on both the left and right side surfaces of the small ridge, and is located at adjacent ends of a pair of adjacent lid bodies. The group of ridges is at least vertical and horizontal The common anti-slip plate is fitted between the opposing engaging grooves of a plurality of small protrusions directly below the anti-slip plate. The plurality of engaging protrusions are integrally provided corresponding to the two sets of protrusion groups.

  Furthermore, the invention of claim 4 is characterized in that, in addition to any of the features of claims 1 to 3, the anti-slip plate is integrally formed of a rubber material or a synthetic resin material. To do.

  Furthermore, the invention of claim 5 is characterized in that, in addition to the feature of any one of claims 1 to 3, the anti-slip plate is composed of a metal plate which is plastically processed as a whole.

  As described above, according to the first aspect of the present invention, the small protrusions formed on the upper surface of the lid main body, which is an extrusion-molded or pultruded product, are formed on the left and right side surfaces of the small protrusion in the molding direction of the lid main body. Each has an engaging groove extending, and the engaging groove of the small ridge located on one side or both sides of at least one set of the ridge group, and the small protrusion of the other group of protruding ridges opposed to the engaging groove. Since an anti-slip plate that can exhibit an anti-slip action in at least two vertical and horizontal directions is fitted between the engagement grooves of the ridges, each ridge group has a sufficient anti-slip function in a direction perpendicular to the molding direction. The anti-slip plate that can exhibit the anti-slip function in multiple directions can be accurately fixed to the upper surface of the lid body between the adjacent ridge groups with the simple structure. While ensuring a good anti-slip function as a whole, cost reduction and assembly workability are improved. It is.

  According to the invention of claim 2, each small protrusion formed on the upper surface of the lid body which is an extrusion-molded or pultruded product is engaged with the left and right sides of the small protrusion extending in the molding direction of the lid body. Each of the grooves has a groove, and at least one set of ridges is covered with a non-slip plate capable of exhibiting an anti-slip action in at least two directions, and the anti-slip plate includes a plurality of anti-slip plates directly below the anti-slip plate. Since the lower surface has engaging protrusions that are respectively fitted between the opposing engaging grooves of the small protrusions, an anti-slip plate that can exhibit an anti-slip function in multiple directions is provided on the upper surface of the lid body. A simple structure using the small ridges of the ridge group can be accurately fixed, which contributes to cost savings and improved assembly workability.

  Further, according to the invention of claim 3, the protrusions are formed on the left and right ends of the upper surface of each of the at least two lid bodies which are extrusion molded or pultruded products and are connected in parallel in the left and right directions. Each of the small ridges constituting the ridge group has engagement grooves extending in the molding direction of the lid main body on both the left and right side surfaces of the small ridge, and at least the left and right ends of the upper surface of each lid body. Two sets of ridge groups, each formed with ridge groups and positioned at adjacent ends of a pair of adjacent lid bodies, are covered with a common anti-slip plate that can exhibit an anti-slip action in at least two directions. The common anti-slip plate has a plurality of engaging protrusions respectively fitted between the opposing engaging grooves of the plurality of small protrusions directly below the anti-slip plate, and corresponds to the two sets of protrusion groups. The anti-slip plate that can demonstrate the anti-slip function in multiple directions The body top surface, becomes precisely fixable with a simple structure using the small protrusion of the protrusion group can contribute to the improvement of the assembling workability and cost savings. Moreover, the anti-slip plate straddles between the two lid bodies adjacent to each other, and can smoothly cover the boundary between the lid bodies, and can also be used as a coupling means between the lid bodies. This can contribute to further structural simplification and cost saving.

  In particular, according to the invention of claim 4, since the anti-slip plate is integrally formed of a rubber material or a synthetic resin material, even if the anti-slip plate has a complicated shape structure, Can be manufactured easily and at low cost.

  In particular, according to the invention of claim 5, since the anti-slip plate is composed of a metal plate which is plastically processed as a whole, the anti-slip plate having high rigidity and durability is used for a long time. A good anti-slip function can be exhibited.

  Embodiments of the present invention will be specifically described below based on the embodiments of the present invention illustrated in the accompanying drawings.

  1 to 5 show a first embodiment of the present invention, in which FIG. 1 is a perspective view of a principal part of a pit groove provided with a pit cover, FIG. 2 is an enlarged perspective view of the pit cover, 3 is an enlarged sectional view taken along line 3-3 in FIG. 2, FIG. 4 is an enlarged sectional view taken along the arrow 4 in FIG. 3, and FIG. 5 is an enlarged sectional view taken along the arrow 5 in FIG. FIG. 6 is an enlarged perspective view (corresponding to FIG. 2) of the pit cover according to the second embodiment of the present invention, and FIGS. 7 and 8 show the third embodiment of the present invention. 7 is an enlarged perspective view of the pit lid (corresponding to FIG. 2), and FIG. 8 is an enlarged sectional view taken along line 8-8 of FIG.

  First, in FIG. 1 to FIG. 5, a pit groove P extending in a predetermined direction is recessed in the installation surface F, and an opening edge portion that forms a pair of openings 1 of the pit groove P has an L-shaped cross section. The lid mounting step 2, which is edged with a rim frame material, is provided so as to be recessed from the installation surface F. On the lid mounting step 2, both side edge portions of a plurality of pit lids T arranged in a row so as to close the opening 1 of the pit P are placed and supported, and the upper surface of each lid T is set in the supported state. It is substantially flush with the surface F and constitutes a walking surface together with the installation surface F.

  The lid body Tm of each pit lid T is formed into a hollow closed cross-sectional structure having a rectangular cross section by extrusion molding or pultrusion of aluminum material, and a plurality of partition walls 3 that divide the hollow body into a plurality of closed cross sections. Are integrally formed.

  Each pit lid T is composed of a plurality (two in the illustrated example) of lid bodies Tm. The lid bodies Tm are arranged in parallel on the left and right sides, and the adjacent end portions of the adjacent lid bodies Tm are described later. The coupling means J is detachably coupled.

  On the upper surface of each lid body Tm, a plurality of sets of ridge groups A, B, each composed of a set of a plurality of small ridges t extending in the forming direction of the extrusion molding or pultrusion molding and arranged close to each other. C are formed apart from each other and simultaneously with the extrusion molding or pultrusion molding, and the positions of the ridge groups A, B, C are at least a part of the left and right end walls 4, 4 'of the lid body Tm. The position corresponds to the partition wall 3. That is, the ridge groups A, B, and C are respectively disposed at the left and right end portions and the middle portion (the center portion in the illustrated example) of the upper surface of each lid main body Tm, and the lateral width (therefore, the small ridge group B is small). The number of ridges t) is twice the lateral width of the ridge groups A and C at the left and right ends (therefore, the number of small ridges t).

  Arc-shaped engagement grooves tg extending in the molding direction are formed on the left and right side surfaces of each small protrusion t, and are located on one side or both sides of each group of protrusion groups A, B, C. Sliding in multiple directions between the engagement groove tg of the small protrusion t and the engagement groove tg of the small protrusion t of another group of protrusions A, B, and C opposite thereto. A rectangular anti-slip plate S with concavities and convexities that can exert a stopping action is fitted (that is, the left and right side edges of the anti-slip plate S are fitted and fixed in a corresponding pair of engaging grooves tg). In this embodiment, a stainless steel strip is used as the anti-slip plate S, and the fitting and fixing of the left and right side edges of the anti-slip plate S to the corresponding engagement grooves tg is, for example, the fitting This is performed by using friction generated based on the appropriate setting of the fitting allowance between the surfaces, or by applying an adhesive between the fitting surfaces.

  Further, in this embodiment, each set of protrusion groups A, B, and C (therefore, a plurality of small protrusions t constituting each protrusion group) are all exposed to the outside and orthogonal to the small protrusions t. The anti-slip action in the direction to be able to be exhibited.

  The coupling means J between the adjacent lid bodies Tm includes a coupling recess 4a formed integrally with the left and right end walls 4 of one lid body Tm, and the other so that the coupling recess 4a can be removably fitted into the coupling recess 4a. It is inserted into the coupling convex part 4a 'formed integrally with the left and right other end wall 4' of the lid body Tm, and the engaging hole 5 formed between the fitting surfaces of the coupling concave part and convex parts 4a, 4a '. And a rod-like engagement tool 6. The coupling operation is performed by fitting the coupling convex portion 4a ′ of the other lid main body Tm into the coupling concave portion 4a of one lid main body Tm and pushing the engaging tool 6 into the engagement hole 5 between the mating surfaces. Completion and release of the connection are performed in the reverse order of the above.

  The coupling recess 4a and the coupling projection 4a ′ exposed at the left and right ends of the pit lid T are covered with dedicated cover pieces 7 and 7 ′, respectively. The coupling recess 4a and the cover piece 7 and the coupling projection 4a ′ and the cover piece 7 ′ are detachably coupled by coupling means Je and Je ′ having the same structure as the coupling means J.

  Next, the operation of the embodiment will be described. In this example of use, as is clear from FIG. 1, each lid body Tm is arranged such that its pushing or pulling direction crosses the pit groove P.

  In such an example of use, in order to assemble the pit lid T from a plurality of lid bodies Tm, a non-slip plate S is mounted in advance on the upper surface of a desired number (two in the illustrated example) of lid bodies Tm, and these lids The main bodies Tm are arranged side by side so that the left and right ends thereof are abutted with each other, and the left and right end faces are integrally coupled to each other by the coupling means J. Also, cover pieces 7, 7 'are integrally coupled to the left and right ends of the pit lid T by coupling means Je, Je'. Thus, the assembly of the pit lid T is completed.

  Thus, according to this embodiment, the small protrusions t in the protrusion groups A, B, and C formed on the upper surface of the lid body Tm, which is an extrusion-molded or pultruded product, are left and right of the small protrusion t. Each side surface has an engagement groove tg extending in the molding direction of the lid main body Tm, and the engagement of the small ridge t located on one side or both sides of at least one set of ridge groups A, B, C. Between the groove tg and the engaging groove tg of the small ridge t of another set of ridge groups A, B, and C opposite to the groove tg, unevenness 9 capable of exhibiting a multidirectional anti-slip action is provided on the upper surface. The attached wide anti-slip plate S is fitted from one end side in the molding direction of the lid main body Tm. Therefore, each of the protrusion groups A, B, C can not only exhibit a sufficient anti-slip function in a direction orthogonal to the molding direction, but also has a wide anti-slip plate S that can exhibit an anti-slip function in multiple directions. Can be accurately fixed to the upper surface of the lid body Tm between adjacent ridge groups A, B, and C with a simple structure using some small ridges t (engagement grooves tg). As a result, it is possible to reduce costs and improve assembly workability while ensuring a good anti-slip function as a whole. Moreover, the pair of left and right engaging grooves tg specially provided on the small protrusion t can be easily and accurately formed simultaneously with the extrusion molding or the pultrusion molding of the lid body Tm.

  Further, in this embodiment, since the anti-slip plate S is composed of a metal plate, particularly a stainless steel strip plate, the anti-slip plate S having high rigidity and durability and good anti-slip for a long period of time. The function can be demonstrated.

  FIG. 6 shows a second embodiment of the present invention. In this embodiment, the anti-slip plate S is the same as that of the first embodiment except that the whole is integrally formed of a rubber material or a synthetic resin material. The same reference numerals as those in the embodiment are given.

  Thus, in this embodiment, even if the upper surface of the anti-slip plate S has a complicated uneven shape, it can be manufactured easily and at low cost. In particular, when the anti-slip plate S is formed of a rubber material, the anti-slip effect is great in combination with the unevenness 9 on the upper surface.

  7 and 8 show a third embodiment of the present invention. In this embodiment, at least a part (a whole in the illustrated example) of the plurality of sets of protrusion groups A, B, C formed on the upper surface of each lid body Tm has unevenness 9 that can exhibit an anti-slip action in multiple directions. Is covered with a relatively narrow strip-shaped anti-slip plate S ', and the lower surface of the anti-slip plate S' is opposed to a plurality of small protrusions t immediately below the anti-slip plate S '. A plurality of engaging projections 8 respectively fitted between the engaging grooves tg are formed in parallel with each other. This anti-slip plate S ′ is integrally formed of a rubber material or a synthetic resin material as in the second embodiment.

  Also, two pairs of protrusion groups A and C located at adjacent ends of a pair of adjacent lid main bodies Tm are congruent with each other with the same width as the central protrusion group B adjacent to each other in the combined state of the two lid main bodies Tm. A ridge group is formed, and the joint ridge groups A and C are covered with a common strip-like anti-slip plate S ′ straddling them. On the lower surface of the common anti-slip plate S ′, a plurality of engaging protrusions 8 are formed in parallel with each other corresponding to the joint protrusion groups A and C, and the engaging protrusions 8 are integrally formed. The plurality of small protrusions t of the joint protrusion groups A and C are respectively fitted between the engaging grooves tg facing each other. The configuration other than the above is basically the same as that of the first embodiment, and the same reference numerals as those of the corresponding components of the first embodiment are given to the respective components.

  Thus, according to the third embodiment, the strip groups A, B, and C arranged on the upper surface of the lid body Tm at a distance from each other can form a strip-like slip that can exhibit an anti-slip action in multiple directions. Each of the anti-slip plates S ′ is covered with a stop plate S ′, and the anti-slip plate S ′ has a plurality of engaging protrusions 8 fitted between the opposing engaging grooves tg of the plurality of small protrusions t just below the lower surface. Since it has a single structure, a non-slip plate S 'capable of exhibiting anti-slip functions in multiple directions is used on the top surface of the lid body Tm, and a simple structure using small ridges t of the ridge groups A, B, C It can be fixed accurately and contributes to cost savings and improved assembly workability.

  In addition, in this embodiment, two sets of ridge groups A and C located at adjacent ends of a pair of adjacent lid bodies Tm are adjacent to each other in the coupled state of both lid bodies Tm, and the central ridge group B Since the joint ridge groups A and C are covered with the common strip-like anti-slip plate S ′ straddling them, The common anti-slip plate S 'can cover the boundary between the two lid bodies Tm, Tm adjoiningly, and the common anti-slip plate S' itself also serves as a coupling means between the lid bodies Tm. Therefore, the structure can be further simplified and the cost can be reduced, and the coupling strength between the two lid bodies Tm can be further enhanced in combination with the coupling effect of the original coupling means J.

  As mentioned above, although the Example of this invention was described, this invention is not limited to these Examples, A various Example is possible within the scope of the present invention. For example, in the above embodiment, the lid body Tm is extruded or pultruded with an aluminum material, but the lid body Tm is a metal material other than an aluminum material that can be extruded or pultruded, or a synthetic resin such as FRP. Extrusion molding or pultrusion molding may be performed with a system material.

  In the first and second embodiments, a relatively wide anti-slip plate S is fitted between the strip groups A, B, and C spaced apart from each other, and the projection groups A, B, and C are exposed. Further, in the third embodiment, such a wide anti-slip plate S is omitted, and each ridge group A, B, C is covered with a belt-like anti-slip plate S ′. Although shown, in the present invention, the anti-slip plate S of the first or second embodiment and the anti-slip plate S ′ of the third embodiment may be used in combination as appropriate.

  In each of the above embodiments, the pit lid T is divided from a plurality of side-by-side lid bodies Tm coupled to each other. However, in the present invention (Claims 1 and 2), the pit lid T is a single unit. You may comprise from one lid | cover main body Tm.

  In each of the above embodiments, the engagement groove tg is formed in an arc shape in cross section. However, in the present invention, the engagement groove tg has at least the anti-slip action on the anti-slip plates S and S ′ as the cross section shape of the engagement groove. For example, it may be formed in a U-shaped cross section or a V shape.

The principal part perspective view of the pit groove which provided the pit cover concerning 1st Example of this invention Enlarged perspective view of the pit lid 3-3 enlarged sectional view of FIG. 4 is an enlarged cross-sectional view taken along arrow 4 in FIG. 3 is an enlarged cross-sectional view taken along the arrow 5 in FIG. Enlarged perspective view showing the second embodiment of the pit lid (corresponding to FIG. 2) Enlarged perspective view showing the third embodiment of the pit lid (corresponding to FIG. 2) FIG. 7 is an enlarged sectional view taken along line 8-8.

Explanation of symbols

A, B, C .. Projection group F ... Installation surface P ... Pit groove T ... Pit cover Tm ... Cover body t ... Small projection tg ... Joint groove S ... Anti-slip plate S '... Anti-slip plate 1 ... Opening 8 ... Engagement projection 9 ... Unevenness

Claims (5)

A pit lid capable of opening and closing the opening (1) of the pit groove (P) recessed in the walking installation surface (F),
At least one lid body (Tm) formed into a hollow closed cross-sectional structure having a rectangular cross section by extrusion molding or pultrusion molding is provided, and a molding direction of the extrusion molding or pultrusion molding is provided on the upper surface of the lid body (Tm). A plurality of sets of protrusions (A, B, C) each composed of a set of a plurality of small protrusions (t) that extend in the vicinity of each other and are arranged in close proximity to each other, and are separated from each other and are extruded or drawn. In what is formed at the same time as molding,
Each of the small ridges (t) has engaging grooves (tg) extending in the molding direction on the left and right side surfaces of the small ridge (t), respectively, and at least one set of ridge groups (A , B, C), the engagement groove (tg) of the small protrusion (t) located on one side or both sides, and the small protrusions of the other group of protrusions (A, B, C) facing this A pit cover, wherein an anti-slip plate (S) capable of exhibiting an anti-slip action in at least two directions is fitted between the engagement groove (tg) of the strip (t). A pit lid capable of opening and closing the opening (1) of the pit groove (P) recessed in the walking installation surface (F),
At least one lid body (Tm) formed into a hollow closed cross-sectional structure having a rectangular cross section by extrusion molding or pultrusion molding is provided, and a molding direction of the extrusion molding or pultrusion molding is provided on the upper surface of the lid body (Tm). A plurality of sets of protrusions (A, B, C) each composed of a set of a plurality of small protrusions (t) that extend in the vicinity of each other and are arranged in close proximity to each other, and are separated from each other and are extruded or drawn. In what is formed at the same time as molding,
Each of the small ridges (t) has engaging grooves (tg) extending in the molding direction on the left and right side surfaces of the small ridge (t), respectively, and at least one set of ridge groups (A, B, C) are covered with a non-slip plate (S ′) capable of exhibiting a non-slip action in at least two directions, and the anti-slip plate (S ′) is a plurality of anti-slip plates (S ′). A pit cover having engaging protrusions (8) fitted respectively between the engaging grooves (tg) of the small protrusions (t) facing each other. A pit lid capable of opening and closing the opening (1) of the pit groove (P) recessed in the walking installation surface (F),
At least two lid bodies (Tm) formed in a hollow closed cross-sectional structure having a rectangular cross section by extrusion molding or pultrusion molding are arranged in parallel on the left and right sides, and between adjacent ends of adjacent lid bodies (Tm). Are detachably coupled,
At least left and right end portions of the upper surface of each lid body (Tm) are protrusions each composed of a set of a plurality of small protrusions (t) extending in the forming direction of the extrusion molding or pultrusion molding and arranged close to each other. A group of strips (A, B, C) are formed at the same time as the extrusion or pultrusion of each lid body (Tm) apart from each other, and each small projection (t) has its small projection ( Two sets of protrusions (A) having engaging grooves (tg) extending in the molding direction on the left and right side surfaces of t) and positioned at adjacent ends of a pair of adjacent lid bodies (Tm). , C) is covered with a common anti-slip plate (S ′) that can exhibit an anti-slip action in at least two directions, the common anti-slip plate (S ′). A plurality of engaging protrusions that are respectively fitted between the opposing engaging grooves (tg) of the plurality of small protrusions (t) immediately below. (8), characterized in that integrally has in correspondence with the two sets of ridges groups (A, C), the pit lid.   The pit cover according to any one of claims 1 to 3, wherein the non-slip plate is integrally formed of a rubber material or a synthetic resin material.   The pit cover according to any one of claims 1 to 3, wherein the anti-slip plate is formed of a metal plate that is plastically processed as a whole.

Images